Method and devices for severing sheets from and/or feeding a web into a subsequent processing stage

Abstract

A web is fed into a sheet severer prior to its entry into a subsequent processing stage. The sheets, which have been severed from the web are then cut into required product sections in a cross-cutter which is associated with this subsequent processing stage. In order to achieve an accurately registered severing process, using the sheet severer, it is triggered by a signal which represents the phase position of the cross-cutter. The sheet severer is thus phase-correlated in relation to the phase position of the cross-cutter.

1. A method for feeding a continuous web including;
 providing a continuous web travel path extending in a web travel direction; 
 providing a web transverse cutting device located at a termination of said continuous web travel path; 
 using said web transverse cuffing device for cutting said continuous web into product sections; 
 providing a first web severing device before, in said web travel direction, and in said web travel path, said web transverse cutting device; 
 generating a signal evidencing a phase relationship of said web at said web transverse cutting device; 
 providing a signal requiring an emergency stop of travel of said web in said web travel direction; 
 severing said web prior to said web transverse cutting device in response to said emergency web stop signal; 
 accomplishing a phase-controlled severing of said web after said emergency severing of said web; 
 generating a fresh web start resulting from said phase-controlled severing of said web after said emergency severing of said web; and 
 directing said fresh web start to said web transverse cutting device. 
 
   
   
     2. The method of  claim 1  further including one of a drive mechanism and a cylinder in said transverse cutting device and generating said signal evidencing said phase relationship at said one of said drive device and said cylinder. 
   
   
     3. The method of  claim 1  further including providing a virtual guide shaft for electronically synchronizing at least one drive mechanism for said transverse cutting device and at least one upstream drive mechanism and generating said signal evidencing said phase relationship from said vertical guide shaft. 
   
   
     4. The method of  claim 1  further including providing a predefined set point phase relationship, comparing said actual phase relationship with said predefined set point phase relationship and sending a singular signal in response to agreement of said phase relationship. 
   
   
     5. The method of  claim 4  further including providing a control unit and using said control unit for checking said signal evidencing said phase relationship with said predefined set point phase relationship. 
   
   
     6. The method of  claim 5  further including stopping said phase-controlled severing of said web in response to no agreement between said set point phase relationship and said phase relationship. 
   
   
     7. The method of  claim 6  further including operating said severing device in response to an agreement between said set point phase relationship and said phase relationship. 
   
   
     8. The method of  claim 1  further including monitoring a width of said continuous web upstream of said transverse web cutting device. 
   
   
     9. The method of  claim 8  further including monitoring said width of said continuous web with respect to a maximum web width which is not to be exceeded. 
   
   
     10. The method of  claim 9  further including accomplishing said phase-correlated severing of said web only if said web width is no greater than said maximum web width value which is not to be exceeded. 
   
   
     11. The method of  claim 9  further including moving said continuous web out of said web travel path while said web width is greater than said maximum web width which is not to be exceeded. 
   
   
     12. The method of  claim 11  further including moving said continuous web out of said web travel path until said web width is no longer greater than said maximum web width which is not to be exceeded and said phase-controlled severing takes place. 
   
   
     13. The method of  claim 1  further including using said first web severing device for accomplishing at least one of said emergency stop signal responsive web severing and said phase-controlled web severing after said emergency severing of said web. 
   
   
     14. The method of  claim 13  further including providing said first web-severing device in an open position, providing first and second cutting elements in said first web-severing device, closing said first and second cutting elements out of an initial position and toward each other in a first degree of freedom for closing said first web-severing device in response to said emergency stop signal, moving at least one of said first and second cutting elements along a second degree of freedom for unblocking said continuous web path of travel, subsequently returning said first and second cutting elements to said initial position along said first and second degrees of freedom and again closing said first and second cutting elements in response to said signal evidencing said phase-relationship from said transverse cutting device. 
   
   
     15. The method of  claim 1  further including providing a second web severing device, using said first web severing device for said accomplishing of said severing of said web in response to said emergency stop signal, and using said second web severing device for said accomplishing of said phase-controlled severing of said web after said emergency severing of said web. 
   
   
     16. The method of  claim 15  further including providing said first and second web severing devices open, receiving said emergency stop signal, closing said first web-severing device while leaving said second web-severing device open, moving said continuous web out of said continuous web path; subsequently closing said second severing device in response to said phase relationship signal, cutting off said continuous web moved out of said continuous web path, moving said continuous web into said continuous web path and conveying said continuous web to said web transverse cuffing device. 
   
   
     17. The method of  claim 1  further including blocking said continuous web travel path in response to said providing said signal requiring said emergency stop of travel of said web. 
   
   
     18. The method of  claim 17  further including providing a controllable shunt in said continuous web travel path and using said controllable shunt for blocking said continuous web travel path. 
   
   
     19. The method of  claim 18  further including providing a blade on said first web severing device and using said blade for blocking said continuous web travel path. 
   
   
     20. The method of  claim 18  further including providing said shunt as one of a hoop and a deflecting tongue. 
   
   
     21. The method of  claim 17  further including sensing a width of said web and cancelling said blocking of said continuous web travel path only if said web width is no greater than a maximum web width value. 
   
   
     22. The method of  claim 1  further including moving said continuous web out of said web travel path until completion of said phase-correlated severing of said web after said emergency severing of said web occurs.